Pesticides in Indian birds

[Mrudul Godbole]

Pesticides in Indian birds
Adam Halliday : Sun Feb 10 2013, 20:51 hrs

Earlier this month, when thousands of migratory harriers arrived at the Narmada, scores of ornithologists, conservationists, water management experts, forest officials, and organic farming lobbyists went into a huddle in Ahmedabad, India. Worried about changes in farming practices in regions surrounding the world’s largest roosting site for harriers in Gujarat’s Bhavnagar district, where an estimated 3000 birds of prey roost for six months post-monsoon, experts tried to chalk out a plan of action to prevent a decimation of this annual congregation due to pesticide levels.

Carnivorous avian species may be the worst-hit non-target organisms if India’s massive use of pesticides is not curbed or controlled, warns a recently published paper titled Status of Pesticide Contamination in Birds in India.India is currently the third largest consumer of pesticides in the world, consuming almost 44,000 metric tonnes in 2009.

In an examination of more than 534 dead birds of 56 species, 300 eggs of 37 species and 140 blood plasma samples of 16 species that lasted eight years, a team led by S Muralidharan of the Salim Ali Centre for Ornithology and Natural History, Coimbatore, detected varying levels of chemical pesticides.

The highest levels showed concentrations of DDE that touched 7,114 parts per billion, but others such as variants of HCH (hexachlorocyclohexane), endosulfan, dieldrin and DDT were also found.

Further, the 10 threatened birds included in the study showed contamination as well—a Nilgiri Wood Pigeon, which is considered vulnerable to extinction, for example showed 6,006 ppb of HCH and a 722 ppb concentration of endosulfan. “Detectable levels of total endosulfan were found in 75 per cent of the samples tested,” the study notes.

The blood plasma of a Sarus Crane, another vulnerable species, showed 286 ppb of HCH. The Nilgiri Pipit, a near threatened species, showed 142 ppb of DDT, while the blood plasma of another near threatened species, Painted Stork, showed DDT concentrations of 147 ppb.

The eggs of a critically endangered White-Rumped Vulture had concentrations of 6,160 ppb of the DDT, a major cause for concern after Diclofenac, used in veterinary treatment of cattle, nearly wiped out vulture populations across India.

“As recently as 1985 the species was described as ‘possibly the most abundant large bird of prey in the world’,” notes an IUCN assessment from 2012, and concludes there may be no more than 15,000 individuals now.

“When all the birds were grouped based on their food habits (frugivorous, granivorous, insectivorous, carnivorous, omnivorous and piscivorous) significantly higher load of pesticide residue was recorded in carnivorous birds,” notes the study.

[Sabyasachi Patra]

Predators often run the risk of accumulation of toxic substances in their bodies when they predate on other prey who inturn consume pesticide laced herbs, shrubs and other plants as well as by drinking pesticide contaminated water.

In the marine ecosystem dolphins have become highly toxic due to pollution of our sea waters. They contain high levels of mercury.

The pesticide residues in the birds can show up many problems including manifestations like genetic defects in newborns impacting the reproduction ability as well as the future generations.

We refuse to learn as our pesticide lobby is powerful. Our politicians increasingly fall in line. Pesticides which have been banned in US and other countries are still being sold in India. Even MNCs have withdrawn products from African countries when lion deaths occurred, but continue to sell in India. For further details please check http://www.indiawilds.com/diary/indi...ol-2-issue-xi/

The Ministry of Chemicals and Fertilisers had done field trials of Neem based pesticides and the trials had gone exceedingly well. Infact, not only the neem based pesticide worked in killing the pests, but also it helped in regeneration ie. it helped as a fertiliser. Unfortunately, there is no lobby for promoting these neem based pesticides inface of the onslaught of the synthetic pesticide lobby.

[Paramvir Singh]

Hi sabyasachi. Are these neem based pesticides safe for birds?

I have always felt that rampant spraying of pesticides to kill mosquitoes in urban cities also destroys smaller harmless bugs, butterflies, caterpillars and beetles, which birds thrive on, thereby reducing bird population in cities.

Wonder what can be done to kill mosquitoes but keep these other bugs safe.

[Sabyasachi Patra]

Hi Paramvir,
There is a difference between neem based pesticides and synthetic pesticides. Neem being available in nature, doesn't have a bad effect on our environment. During our childhood days, whenever someone had skin infection, the person was asked to take bathe in neem water. Neem branches and leaves were kept on beds of people etc. Some farmers are also just crushing the neem leaves, mixing with water and spraying it. Some farmers in Kerala are experimenting by mixing it with some other stuff like cow urine etc.

Our soil has become toxic due to the indiscriminate usage of synthetic fertilisers and pesticides. We need to get rid of those immediately.

Human race and mosquitoes are at war since time immemorial. Despite this, both these species are multiplying at nearly equal pace. They are evolving including genetic changes to combat the challenge of the other. For example, the people living in rainforests developed a physiological adaptation to the Plasmodium falciparum which is transmitted through mosquitoes. This physiological adaptation is known as sickle cell anemia where the hemoglobin takes the form of a sickle (daa in bengali) or crescent. This abnormal sickle celled hemoglobin doesn't allow the plasmodium to multiply as it bursts.

WHO has been trying many things including distributing mosquito nets treated with chemicals. Nothing has been successful. I am an optimist, however, I don't expect this war between mosquitoes and humans to end soon. Nor will both these species see any decline in their population.